Refactor the whole project

This pull request is related to #368.

I finally finished to refactor the project following the model I proposed [here](https://github.com/excilys/androidannotations/issues/368#issuecomment-18602600).

I changed the structure so the code has just been moved and has been modified as less as possible.
Then, all the tests are passing and the generated code is very often the same as it was before.

Good luck for the review ;)